The purpose of this research is to study (1) mechanisms of neural excitation and signal transmission and (2) processing of visual information by recording intracellularly from single cells in the vertebrate and Drosophila retinas. Our specific aims are (1) to study properties of the intracellularly recorded receptor potentials in order to help elucidate mechanisms of physiological excitation and the transmission of excitation in the receptors (2) to study potential productions in other retinal neurons, and (3) to study contributions of the photorecptors and other retinal neurons to the integration of information by the retina. In the case of Drosophila, these studies will be carried out by electrophysiologically comparing visually defective mutants with wild type.